In order to exploit the available frequency spectrum more efficiently, current wireless communication standards require a tight arrangement of communication channels in the frequency domain. As a result, transmit energy from a nearby transmitter (which may be referred to as a transmit blocker signal) can interfere with the receive signal due to the proximity of the transmit antenna to one or more receive antennas. While in particular current digital signal processing techniques exist that enable receivers to filter out a desired signal from a relatively strong noise floor (i.e., a relatively low signal-to-noise (SNR) ratio), a so-called blocker signal, interferer signal, or interference signal that is at a nearby frequency and has a signal level comparable to or even higher than the desired signal, poses a challenge to most receiver structures. In particular, a receiver module needs to process the transmit locker signal and the desired signal with relatively high fidelity, so that the transmit blocker signal may be separated from the desired signal
Carrier aggregation diversity receive (DRX) modules need to have two or more signal paths active at the same time. Traditional carrier aggregation DRX modules use individual receive filters to reject the transmit blocker for each receive path. This approach results in high complexity filters for each path, which leads to higher costs and a larger size for the DRX modules.
It would be desirable to have a DRX module that rejects the transmit blocker for all diversity RX paths simultaneously, while reducing the complexity, size, and costs of the DRX module. Further, it is important to maintain a reasonable quality (Q) actor and provide sizeable band-pass rejection, while still keeping noise low. It would be beneficial to have high transmit blocker rejection and low insertion loss impact in the pass-band filters. It would also be beneficial to have tunability and the ability to cover several adjacent bands so that a wide variety of channel carrier aggregation combinations can be addressed with a small hardware infrastructure.
The present disclosure describes a receive module infrastructure that significantly reduces the complexity, size, and cost of the receive module, while giving reasonable Q factor in matching networks and providing sizeable band-pass rejection, and keeping the noise contribution of the low noise amplifiers (LNAs) low. The proposed receive module infrastructure provides high transmit blocker rejection and low insertion loss impact in the pass-band filters. The proposed receive module infrastructure can address a wide variety of channel carrier aggregation combinations with a small hardware infrastructure.